Electro Magnetic Fields and Home Power Systems

The energy that surrounds us is part of our environment. Recently we've been made aware that the electromagnetic fields (EMFs) made by electric power present a potential health hazard. This article begins a series of two articles about electromagnetic fields. This first article discusses the potential health hazards involved. This first article also defines an electromagnetic field, describes how these fields are produced by electricity, and tells how to construct an ac magnetic field meter to measure the magnetic portion of the fields around our homes. The second article, appearing in our next issue (HP#24), details how to reduce man-made electromagnetic fields and our exposure to these fields.

Life in Electromagnetic Fields

The reason we became interested in electromagnetic fields was medical information about their effect on humans. This information suggests that there may be links between prolonged exposure to electromagnetic fields and diseases, specifically cancer, nervous disorders, and birth defects. The medical community is far from agreement about how much EMF exposure constitutes how much of a health hazard. In fact, I've found the medical view of EMFs to be very confusing and contradictory. I have included a bibliography to some of the medical literature about this at the end of this article. Then you can read the literature & become as befuddled as I am about the hazards involved in EMF exposure.

The medical and electric power communities will be disagreeing about the biological effects of electromagnetic fields years from now. However everyone agrees on one point. This point of agreement is: "There is no minimum daily requirement for electromagnetic fields." Regardless of what medical view you may believe, everyone can agree that no exposure to electromagnetic fields will not harm you.

This article is not presented to scare anyone. In fact, home power users live in electrical environments that naturally have very low electromagnetic fields. This is because most of us don't have commercial power lines connected to our homes. On the other hand, we do make 120 vac power with inverters and generators. These devices do indeed produce EMFs, although much lower in intensity than say, living next to a power line. In fact, every living thing on this planet is constantly bathed in electromagnetic fields produced by the Earth itself. These natural fields are mostly DC in nature and life has evolved in their presence. The Earth's fields present no health hazard because we are used to them. It is the area of human created fields in the 50 to 60 cycle per second range (Hz.) that are potentially hazardous. And this frequency range is where electric power operates.

Cancer

If no one really knows if EMFs are a health hazard, then why be concerned at all? Because some studies have reached very disturbing conclusions. For example, a survey conducted by Nancy Wirtheimer and Edward Leeper in Denver, Colorado during 1979, published in the American Journal of Epidemiology, linked childhood leukemia deaths to prolonged exposure to EMFs. During the last ten years, twelve studies have been done inside the USA linking increased cancer rates to electromagnetic fields. These studies report a 140% to 320% increase in cancer among people with prolonged or intense exposure to electromagnetic fields. It seems that exposure to EMFs interferes with normal cell development by altering the action of RNA within individual cells. The electromagnetic field affects the operation of the living cell by "jamming" normal electrochemical activity and normal growth. This situation is analogous to power line interference on a radio.

Birth Defects

The effect of EMFs on the unborn were studied by Dr. David Savitz, Dr. Esther John and Dr. Robert Klechner and were reported in the May 1990 issue of the American Journal of Epidemiology. They found that the incidence of brain tumors among the children of pregnant women who slept under electric blankets increased two-and-a-half times. They also found a 70% increase in leukemia and a 30% increase in all cancers.

Nervous Disorders

Low-frequency EMFs affect the body's circadian rhythms by affecting the production of a hormone called melatonin which is produced by the brain's pineal gland. Melatonin is a hormone that regulates the biological rhythms of mammals. Research done by Barry Wilson and his co-workers at Battelle Pacific Northwest Labs has documented that prolonged exposure to EMFs causes reduction in the secretion of melatonin. Reduction of melatonin levels can result in psychiatric disorders like depression, shortened attention span, & inability to sleep.

The jury is still out...

For every study I have cited above there is also a study that says that EMFs pose no danger to living creatures. The point here is that we can live very well without exposure to the electromagnetic fields produced by electric power. So let's understand what EMFs are, let's measure our exposure to them, and finally let's reduce our exposure to EMFs to a minimum.

What is an Electromagnetic Field?

All energy which radiates is electromagnetic radiation. Radiant energy comes in many forms and is usually classified by frequency. Light is electromagnetic radiation of a very high frequency, and radio is electromagnetic radiation that is lower in frequency. All electromagnetic radiation is surrounded by what is called an electromagnetic field. Electromagnetic fields are composed of two components, one is electric and the other magnetic. These two fields are at right angles to each other and are inherent in all types of radiation. The illustration below graphically represents a moving electromagnetic wave with its electric and magnetic components.

How are Electromagnetic Fields Made?

The electric portion of an electromagnetic field is caused by electric charge. The electric portion is usually called "the electrostatic field" and for our purposes is related to voltage. The magnetic portion of the field is caused by charge in motion. This magnetic portion is usually called

ELECTRIC

FIELD

VECTOR

MAGNETIC FIELD 'VECTOR

ELECTRIC

FIELD

VECTOR

MAGNETIC FIELD 'VECTOR

"the magnetic field" and is, for our purposes, related to current (electrons in motion). In simple terms, voltage creates the electric component, while current causes the magnetic component.

The electric fields encountered at voltages lower than 440 Volts are very weak and do not present appreciable health hazards. Since home power users only use voltages below »220 volts, we don't need to be concerned with the electric fields within our homes. The same, however, cannot be said about magnetic fields.

The intensity of a magnetic field is directly proportional to the amount of current flowing. More amps means more intense magnetic fields. And it is the magnetic portion of the electromagnetic field that needs our attention.

Magnetic fields follow the inverse square law of radiant energy. This means that the closer you are to the field's source, the much intense the field is. If you halve the distance between yourself and the field, then the field is four times more intense.

How are ac Magnetic Fields Measured?

The intensity of a magnetic field is expressed in two units, one is called the Gauss and the other is called the Tesla. One Tesla is equal to 10,000 Gauss. In this article we will be using the unit called milliGauss, which is one-thousandth of a Gauss. To give you an feeling for the intensity of a magnetic field, consider the following data supplied by an electric power utility (the Bonneville Power Administration). If you stand underneath a 500 kilovolt power line you will be in a magnetic field which has a peak of 140 milliGauss. But since magnetic fields are related not only to current flow but also to our proximity to the current flow you don't have to stand underneath a power line to be in the presence of an intense magnetic field. Consider these household magnetic fields. The magnetic field for those who sleep under a 120 vac electric blanket are up to 100 milliGauss. The electric blanket is so dangerous because it is very close to the body for extended periods of time. At a distance of one foot, the magnetic field surrounding a microwave oven is about 40 to 80 milliGauss, and the fields around electric hair dryers and electric shavers range from 1 to 90 milliGauss. At a distance of one foot, fluorescent lighting and TV sets have fields in the range of 1 to 20 milliGauss. This is what electric power utilities are telling us. We are skeptical and decided to measure the fields in our environment ourselves. And the

Health & Environment remainder of this article details the instruments we constructed to accomplish these measurements and our findings.

So, how much is too much?

As we stated before, the health community and the power utilities are in radical disagreement on how much magnetic field exposure is too much. Suffice it to say that the state of Florida has set a 250 milliGauss maximum on the edge of their power line right-of ways.

The health studies we read state that fields over 100 milliGauss can most certainly produce health effects. Fields as low as 1 milliGauss can be dangerous if a body is exposed to them for long periods of time. We measure the intensity of the background ac magnetic fields outside in our "quiet" rural environment at less than 0.15 milliGauss.

So how can you find out the intensity of the magnetic fields in your home? Well, get a milliGauss meter and measure them. That's what we did. We built our own milliGauss meters and had them calibrated by an authority who does magnetic field work for a major utility. This person was of immense help in constructing and calibrating our meters. We'd give you his name, but he likes his job of convincing the power companies to clean up their act, and prefers to remain anonymous.

If you don't want to build your own milliGauss meter, then purchase one already made. A list of suppliers of already made milliGauss meters appears in Access at the end of this article.